I'd like to get a better sense of how you might use ADFS. When you state that you need "federation," what are you wanting to do? I imagine most scenarios involve applications on Amazon EC2 instances obtaining tokens from an ADFS server located inside your corporate network. This makes sense when your users are in your own domains and the applications running on Amazon EC2 are yours.

Another scenario involves a forest living entirely inside Amazon EC2. Imagine you've created the next killer SaaS app. As customers sign up, you'd like to let them use their own corpnet credentials rather than bother with creating dedicated logons (your customers will love you for this). You'd create an application domain in which you'd deploy your application, configured to trust tokens only from the application's ADFS. Your customers would configure their ADFS servers to issue tokens not for your application but for your application domain ADFS, which in turn issues tokens to your application. Signing up new customers is now much easier.

What else do you have in mind for federation? How will you use it? Feel free to join the discussion. I've started a thread on the forums, please add your thoughts there. I'm looking forward to some great ideas.

AWS-Powered Walkshed is a finalist in the NYC Big Apps Contest and they need your vote in order to win!

Built by Philadelphia-based Avencia, Walkshed combines 10 data sources chosen from the NYC Data Mine to compute and display personalized walkability maps based on a set of seventeen priorities such as proximity to grocery stores, farmer's markets, restaurants, bars, Zipcars, playgrounds, bookstores, and Wifi hotspots.

The Walkshed front end was implemented in ASP.NET and runs within Apache Tomcat. The tile serving API was written in Ruby on Rails and requests map tiles from Avencia's DecisionTree service, itself a .Net application written in C#. Here's what it looks like:

Hosting for Walkshed is handled on a dynamic hybrid model. A private VMWare server handles routine traffic. Three High-CPU Extra LargeAmazon EC2 instances running Microsoft Windows are used to improve fault tolerance and to handle traffic bursts. The EC2 instances use the new boot from EBS feature to improve boot speed. They also make use of Amazon Cloudfront; an article on one of their previous successes with CloudFront can be found here.

The Varnish HTTP accelerator handles caching of frequently requested files and heatmap tiles and scaling (via load balancing). Varnish also improves reliability and availability by retrying failed requests and monitoring the health of the servers.

If you think that this is cool, consider taking a minute or two to vote for it!